Cleaning sheet, conveying member using the same, and substrate processing equipment cleaning method using them

ABSTRACT

A cleaning sheet has a cleaning layer having a surface resistivity not less than 1×1013 Ω/□. In a method of manufacturing a conveying member with a cleaning function, for sticking the cleaning sheet, in which the cleaning layer formed of an adhesive that is polymerized/cured by an active energy is provided onto one surface of a base material and an ordinary adhesive layer is provided onto the other surface thereof, onto the conveying member via an ordinary adhesive layer to have a shape larger than the shape of the conveying member and then cutting the cleaning sheet along a shape of the conveying member, wherein a polymerizing/curing reaction of the cleaning layer is carried out after the cleaning sheet is cut out into the shape of the conveying member.

INFORMATION

DETAILED DESCRIPTION OF THE INVENTION

EXAMPLE 1

The ultraviolet curing adhesive solution was formed by mixing uniformly the polyethylene glycol dimethacrylate 50 parts, the urethane acrylate 50 parts, the benzyldimethylketal 3 parts, and the diphenylmethanediisocyanate 3 parts into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts.

In contrast, the ordinary adhesive layer was provided by coating the adhesive solution, that was obtained in the same way except that the benzyldimethylketal was removed from the above adhesive, on one surface of the polyester base material film, that had a width of 250 mm and a thickness of 25 μm, to have a thickness of 10 μm after the drying, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. The adhesive layer is provided as the cleaning layer by coating the above ultraviolet curing adhesive solution on another side of the base material film to have a dried thickness of 40 μm, whereby the similar releasing film was pasted on the surface.

The cleaning sheet of the present invention was obtained by irradiating the ultraviolet rays having a central wavelength 365 nm by an integrated quantity of light 1000 mJ/cm2 onto this sheet. When the surface resistivity was measured via the cleaning layer by the surface resistivity measuring device (type MCP-UP450 manufactured by Mitsubishi Chemical Industries Ltd.) at the temperature of 23° C. and the humidity of 60% after the releasing film on the cleaning layer side of this cleaning sheet was peeled off, it was impossible to measure the surface resistivity if such surface resistivity exceeds 9.99×1013 Ω/□.

Also, when the adhesive layer on the cleaning layer side was pasted onto the mirror surface of the silicon wafer to have a width of 10 mm and then the 180° releasing adhesive force for the silicon wafer was measured based on JIS Z0237, 0.078 N/10 mm was obtained.

The conveying cleaning wafer with the cleaning function was fabricated by peeling off the releasing film on the ordinary adhesive layer side of this cleaning sheet and then pasting this film onto a back surface (mirror surface) of the 8-inch silicon wafer by the hand roller.

In contrast, when two wafer stages of the substrate processing equipment were removed and then the number of the foreign matter having a size of not less than 0.3 μm was counted by the laser foreign-matter measuring device, 25000 foreign matters were counted in one area of the 8-inch silicon wafer size and 22000 foreign matters were counted in another area thereof.

Then, when the releasing film on the cleaning layer side of the resultant conveying cleaning wafer was peeled off and then the wafer was conveyed into the substrate processing equipment that has the wafer stage to which the 25000 foreign matters were adhered, the wafer could be conveyed without trouble. Then, when the wafer stage was removed and the number of the foreign matter having a size of more than 0.3 μm was counted by the laser foreign-matter measuring device, 6200 foreign matters were counted in the 8-inch silicon wafer size. Thus, the foreign matters adhered before the cleaning could be removed in number by ¾ or more.

Comparative Example 1

When the cleaning sheet was fabricated in the same way as Example 1 other than that the additive (product name V-SQ-S6 manufactured by Mitsubishi Chemical Industries Ltd.) 5 parts that have the 4-th class ammonium salt having the conducting function in the side chain was added into the adhesive layer of the cleaning layer and then the surface resistivity of the cleaning layer was measured in the same way, 5.5×1011 Ω/□ was obtained. Also, when the adhesive force of the adhesive layer of the cleaning layer to the silicon wafer was measured, 0.33 N/10 mm was obtained.

When the conveying cleaning wafer fabricated in the same way as Example 1 from this cleaning sheet is conveyed into the substrate processing equipment that has the wafer stage to which the 22000 foreign matters are adhered, the wafer can be conveyed without trouble. Then, when the wafer stage was removed and the number of the foreign matter having a size of not less than 0.3 μm was counted by the laser foreign-matter measuring device, 20000 foreign matters were counted in the 8-inch silicon wafer size. Thus, the foreign matters adhered before the cleaning could be removed in number merely by about {fraction (1/11)}.

EXAMPLE 2

The ultraviolet curing adhesive solution was formed by mixing uniformly the dipentaerythritolhexacrylate (product name UV1700B manufactured by The Nippon Synthetic Chemical Industry, Co., Ltd.) 150 parts, the benzyldimethylketanol 5 parts, and the diphenylmethanediisocyanate 3 parts into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts.

In contrast, the adhesive solution was obtained in the same way as above except that the benzyldimethylketanol is removed from the above adhesive.

The ordinary adhesive layer was provided by coating the above adhesive solution on one surface of the polyethylene terephthalate, that had a width of 250 mm and a thickness of 25 μm, as the base material to have a dried thickness of 10 μm, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. Also, the adhesive layer was provided as the cleaning layer by coating the above ultraviolet curing adhesive solution on the other side of the base material to have a dried thickness of 20 μm, whereby the similar releasing film was pasted on the surface.

The cleaning sheet A of the present invention was obtained by irradiating the ultraviolet rays having a central wavelength 365 nm by an integrated quantity of light 2000 mJ/cm2 onto this sheet. When the relative dielectric constant of the cleaning layer of this cleaning sheet was measured by the LCR meter (Type 4284A manufactured by Hewlett Packard Co., Ltd.) at 1 MHz, 2.8 was obtained.

EXAMPLE 3

The cleaning sheet B of the present invention was obtained by providing the ordinary adhesive layer in the same way as Example 2 on one surface of the polyethylene terephthalate film (width 250 mm, thickness 25 μm) whose relative dielectric constant is 3.2 and then pasting the similar releasing film on the surface.

The conveying cleaning wafers A and B with the cleaning function were fabricated by peeling off the releasing film on the ordinary adhesive layer side of the resultant cleaning sheets A and B and then pasting the film on the back surface (mirror surface) of the 8-inch silicon wafer by the hand roller.

In contrast, when the foreign matters having a size of more than 0.2 μm on the mirror surfaces of three sheets of new 8-inch silicon wafers were counted by the laser foreign-matter measuring device, 11 foreign matters were counted on the first sheet, 10 foreign matters were counted on the second sheet, and 8 foreign matters were counted on the third sheet. When these wafers were conveyed into the substrate processing equipment that has separate electrostatic adsorbing mechanisms while directing the mirror surface downward and then the mirror surfaces were measured by the laser foreign-matter measuring equipment, 32004, 25632, and 27484 foreign matters were counted in the area of the 8-inch wafer size respectively.

Then, when the releasing films on the cleaning layer side of the resultant conveying cleaning wafers A, B were peeled off and then the wafers were conveyed into the substrate processing equipment that has the wafer stages to which the above 32004 and 27484 foreign matters were adhered respectively, the wafer could be conveyed without trouble. Then, the new 8-inch silicon wafers to which 10 and 13 foreign matters having a size of not less than 0.2 μm were conveyed while directing the mirror surface downward and then the foreign matters having the size of not less than 0.2 μm were counted by the laser foreign-matter measuring device. This process was carried out five times, and the results are shown in Table 1.

Comparative Example 3

The cleaning sheet C was obtained in the same way as Example 3 other than that the polytetrafluoroethylene whose relative dielectric constant is 2.0 was used as the film in Example 3.

The conveying cleaning wafer C that was fabricated in the same way as Example 3 from the cleaning sheet was conveyed into the substrate processing equipment that has the wafer stage to which the 25632 foreign matters were adhered. This operation was repeated five times like Example 3, and the results are shown in Table 1.

EXAMPLE 4

The ultraviolet curing adhesive solution was prepared by mixing uniformly the polyethylene glycol 200 dimethacrylate (product name NKester4G manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, the urethane acrylate (product name U-N-01 manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, and the polyisocyanate compound (product name Colonate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 3 parts, and the benzyldimethylketal (product name Illugacure 651 manufactured by Chiba-Speciality Chemicals Co., Ltd.) 3 parts as the photopolymerization initiator into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts.

In contrast, the ordinary adhesive layer was provided by coating the adhesive solution, that was obtained in the same way except that the benzyldimethylketal as the photopolymerization initiator was removed from the above adhesive solution A, on one surface of the polyester base material film, that had a width of 250 mm and a thickness of 25 μm, to have the dried thickness of 10 μm, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. Then, the adhesive layer as the cleaning layer was provided by coating the above ultraviolet curing adhesive solution A on the other side of the base material film to have the dried thickness of 10 μm, whereby the similar releasing film was pasted on the surface.

The cleaning sheet of the present invention was obtained by irradiating the ultraviolet rays having a central wavelength 365 nm until an integrated quantity of light 1000 mJ/cm2 onto this sheet. Then, the releasing film on the cleaning layer side of this cleaning sheet was peeled off. The measured surface free energy of the cleaning layer was 40.1 mJ/m2, and the measured contact angle with respect to water was 78.2 degree.

The conveying cleaning wafer with the cleaning function was fabricated by peeling off the releasing film on the ordinary adhesive layer side of this cleaning sheet and then pasting this film onto a back surface (mirror surface) of the 8-inch silicon wafer by the hand roller.

In contrast, when two wafer stages of the substrate processing equipment were removed and then the number of the foreign matter having a size of not less than 0.3 μm was counted by the laser foreign-matter measuring device, 25000 foreign matters were counted in one area of the 8-inch silicon wafer size and 23000 foreign matters were counted in another area thereof.

Then, when the releasing film on the cleaning layer side of the resultant conveying cleaning wafer was peeled off and then the wafer was conveyed into the substrate processing equipment that has the wafer stage to which the 25000 foreign matters are adhered, the wafer could be conveyed without trouble. Then, when the wafer stage was removed and the number of the foreign matter having a size of more than 0.3 μm was counted by the laser foreign-matter measuring device, 4800 foreign matters were counted in the 8-inch silicon wafer size. Thus, the foreign matters adhered before the cleaning could be removed in number by ⅘ or more.

Comparative Example 4

A cleaning sheet was formed in the same manner as the Example 4 except for using an ultraviolet curing adhesive solution B prepared by mixing uniformly the dipentaerythtorolhexaacrylate (product name UV1700B manufactured by The Nippon Synthetic Chemical Industry, Co., Ltd.) 100 parts, and the polyisocyanate compound (product name Colonate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 3 parts, and the benzyldimethylketal (product name Illugacure 651 manufactured by Chiba-Speciality Chemicals Co., Ltd.) 10 parts as the photopolymerization initiator into the acrylic polymer (weight-average molecular weight 2800000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 30 parts, the methyl acrylate 70 parts, and the acrylic acid 10 parts. The measured surface free energy of the cleaning layer was 24.6 mJ/m2, and the measured contact angle with respect to water was 82.3 degree.

Then, a conveying cleaning wafer obtained by the same manner as in the Example 4 was conveyed into the substrate processing equipment that has the wafer stage to which the 23000 foreign matters are adhered, the wafer could be conveyed without trouble. Then, when the wafer stage was removed and the number of the foreign matter having a size of more than 0.3 μm was counted by the laser foreign-matter measuring device, 20000 foreign matters were counted in the 8-inch silicon wafer size. Thus, the foreign matters adhered before the cleaning could be removed only in number by about ⅛.

EXAMPLE 5

The ultraviolet curing adhesive solution was formed by mixing uniformly the dipentaerythtorolhexaacrylate (product name UV1700B manufactured by The Nippon Synthetic Chemical Industry, Co., Ltd.) 150 parts, the benzyldimethylketanol 5 parts, and the diphenylmethanediisocyanate 3 parts into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, the acrylic acid 5 parts.

In contrast, the ordinary adhesive layer was provided by coating the adhesive solution, that is obtained in the same way except that the benzyldimethylketal was removed from the above adhesive, on one surface of the polyethylene terephthalate base material film, that has a width of 250 mm, a thickness of 70 μm, and a tensile strength of 250 Mpa to have the dried thickness of 10 μm, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. The cleaning layer was provided by coating the above ultraviolet curing adhesive solution on the other side of the base material film to have the dried thickness of 40 μm, whereby the similar releasing film was pasted on the surface.

The ultraviolet rays having a central wavelength 365 nm was irradiated by an integrated quantity of light 2000 mJ/cm2 onto this sheet from the cleaning layer side, then the releasing film on the cleaning layer side is peeled off, then the cleaning layer was inserted between the electrodes in the atmosphere by employing the thermal electret method, then the voltage of 20 kV is applied at the temperature of 100° C., then the cleaning layer was cooled down to 40° C. while applying the voltage as it is, and then the application of the voltage was ended to form the cleaning layer as the electret. When the surface potential was measured at an electrode-sample interval of 20 mm by the static electricity measuring device (Model FMX002 manufactured by Simco Japan Co. Ltd.) under conditions of 25° C. and 55% RH, 15 kV was obtained. Also, the surface of the cleaning layer did not substantially have the tackiness, and the modulus of elasticity in tension of the cleaning layer after the ultraviolet curing was 1980 N/mm2.

The conveying cleaning wafer with the cleaning function was fabricated by peeling off the releasing film on the ordinary adhesive layer side of the resultant cleaning sheet and then pasting the film on the back surface (mirror surface) of the 8-inch silicon wafer by the hand roller.

In contrast, when the foreign matters having a size of more than 0.2 μm on the mirror surfaces of two sheets of new 8-inch silicon wafers are counted by the laser foreign-matter measuring device, 11 foreign matters were counted on the first sheet, and 10 foreign matters were counted on the second sheet. When these wafers were conveyed into the substrate processing equipment that has separate electrostatic adsorbing mechanisms while directing the mirror surface downward and then the mirror surfaces are measured by the laser foreign-matter measuring equipment, 32004 and 25632 foreign matters were counted in the area of the 8-inch wafer size respectively.

Then, when the releasing film on the cleaning layer side of the resultant conveying cleaning wafer was peeled off and then the wafer is conveyed into the substrate processing equipment that has the wafer stages to which the above 32004 and 27484 foreign matters were adhered respectively, the wafer can be conveyed without trouble. Then, the new 8-inch silicon wafers to which the 10 foreign matters having the size of more than 0.2 μm were conveyed while directing the mirror surface downward and then the foreign matters having the size of more than 0.2 μm were counted by the laser foreign-matter measuring device. This process was repeated five times, and the results are shown in Table 2.

Comparative Example 5

When the cleaning sheet was obtained in the same way as Example 5 other than that the additive (product name V-SQ-S6 manufactured by Mitsubishi Chemical Industries Ltd.) 20 parts that have the 4-th class ammonium salt having the conducting function in the side chain was added into the cleaning layer in the cleaning sheet in Example 5. The surface potential of the cleaning layer measured after the irradiation of the ultraviolet rays like Example 5 was 0.04 kV, and the modulus of elasticity in tension was 1720 N/mm2.

The conveying cleaning wafer that was fabricated in the same way as Example 5 from the cleaning sheet was carried out five times into the substrate processing equipment that has the wafer stage to which the 25632 foreign matters were adhered, like Example 5. The results are shown in Table 2.

EXAMPLE 6

The ultraviolet curing adhesive solution was prepared by mixing uniformly the polyethylene glycol 200 dimethacrylate (product name NKester4G manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, the urethane acrylate (product name U-N-01 manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, and the polyisocyanate compound (product name Colonate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 3 parts, and the benzyldimethylketal (product name Illugacure 651 manufactured by Chiba-Speciality Chemicals Co., Ltd.) 3 parts as the photopolymerization initiator into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts.

In contrast, the ordinary adhesive layer was provided by coating the adhesive solution, that was obtained in the same way except that the benzyldimethylketal as the photopolymerization initiator was removed from the above adhesive solution A, on one surface of the polyester base material film, that has a width of 250 mm and a thickness of 25 μm, to have the dried thickness of 10 μm, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. Then, the adhesive layer as the cleaning layer was provided by coating the above ultraviolet curing adhesive solution A on the other side of the base material film to have the dried thickness of 10 μm, whereby the similar releasing film was pasted on the surface.

The cleaning sheet of the present invention was obtained by irradiating the ultraviolet rays having a central wavelength 365 nm until an integrated quantity of light 1000 mJ/cm2 onto this sheet. Then, the releasing film on the cleaning layer side of this cleaning sheet was peeled off, the coefficient of friction of the cleaning layer after the ultraviolet rays curing was 1.7, and the modulus of elasticity in tension of the cleaning layer after the ultraviolet curing was 50 N/mm2. Here, the coefficient of friction was calculated by moving the stainless steel plate of 50 mm×50 mm under the vertical load 9.8 N at a velocity of 300 mm/min along the predetermined direction in parallel with the surface of the cleaning layer, and then measuring the frictional resistance force generated at that time by the universal tension tester. Also, the modulus of elasticity in tension was measured based on the test method JIS K7127.

The conveying cleaning wafer with the cleaning function was fabricated by peeling off the releasing film on the ordinary adhesive layer side of this cleaning sheet and then pasting the film on the back surface (non-cleaned surface) of the contact pin cleaner (product name Passchip manufactured by PASS Co., Ltd.) as the contact pin cleaning member for the 8-inch silicon wafer shape by the hand roller.

Then, when the cleaning of the contact pins and the cleaning of the chuck table were by peeling off the releasing film on the cleaning layer side of the cleaning member and then dummy-conveying through the wafer probe as the conduction testing device in the semiconductor manufacturing, the cleaning layer was not strongly brought into contact with the contact portion at all and thus the cleaning layer could be conveyed without problem.

Also, when the contact pins were watched by the microscope thereafter, the foreign matters such as the oxide, etc. adhered to the pin before the cleaning were eliminated, and their cleaning can be checked. Also, the silicon waste having a size of about 1 mm, etc. appeared on the chuck table before the cleaning could be completely cleaned, and their cleaning could be found. Then, when 25 sheets of product wafers were conveyed to perform the test actually, the process could be carried out not to cause the problem.

EXAMPLE 7

The ultraviolet curing adhesive solution A was prepared by mixing uniformly the polyethylene glycol 200 dimethacrylate (product name NKester4G manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, the urethane acrylate (product name U-N-01 manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 parts, and the polyisocyanate compound (product name Colonate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 3 parts, and the benzyldimethylketal (product name Illugacure 651 manufactured by Chiba-Speciality Chemicals Co., Ltd.) 3 parts as the photopolymerization initiator into the acrylic polymer (weight-average molecular weight 700000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts.

In contrast, the normal pressure-sensitive adhesive solution A was obtained in the same way as above except that the benzyldimethylketanol was removed from the above adhesive.

The ordinary adhesive layer was provided by coating the above pressure-sensitive adhesive solution A on one surface of the polyester base material film, that had a width of 250 mm and a thickness of 25 μm, to have a dried thickness of 10 μm, whereby the polyester releasing film of 38 μm thickness was pasted on the surface. Also, the adhesive layer was provided as the cleaning layer by coating the above ultraviolet curing adhesive solution A on the other side of the base material to have the dried thickness of 30 μm, whereby the similar releasing film was pasted on the surface. Thus, the cleaning sheet A was fabricated.

When the modulus of elasticity in tension (test method JIS K7127) of this ultraviolet curing adhesive solution A was measured, 0.1 N/mm2 was obtained if the curing reaction was executed by the ultraviolet rays, while 49 N/mm2 was obtained after the ultraviolet rays having the central wavelength 365 nm were irradiated up to the integrated quantity of light 1000 mJ/cm2.

By using this cleaning sheet A, the sheet was pasted onto the wafer by the direct cutting system tape sticker (NEL-DR8500II manufactured by Nitto Seiki Co., Ltd.). At this time, the sheet A was pasted onto the back surface (mirror surface) of the 8-inch silicon wafer and then cut into the wafer shape by the direct cut. When this operation for 25 sheets was carried out successively, the cutting scobs were not generated at all in cutting the sheet.

Then, the conveying cleaning wafer A with the cleaning function was fabricated by irradiating the ultraviolet rays having the central wavelength 365 nm to five sheets of these wafers up to the integrated quantity of light 1000 mJ/cm2.

In contrast, when the foreign matters having a size of more than 0.2 μm on the mirror surfaces of four sheets of new 8-inch silicon wafers were counted by the laser foreign-matter measuring device, 8 foreign matters were counted on the first sheet, 11 foreign matters were counted on the second sheet, 9 foreign matters were counted on the third sheet, and 5 foreign matters were counted on the fourth sheet. When these wafers were conveyed into the substrate processing equipment that has separate electrostatic adsorbing mechanisms while directing the mirror surface downward and then the mirror surfaces were measured by the laser foreign-matter measuring equipment, 31254, 29954, 28683 and 27986 foreign matters were counted in the first, second, third, and fourth areas of the 8-inch wafer size respectively.

Then, when the releasing film on the cleaning layer side of the resultant conveying cleaning wafer A was peeled off and then the wafer was conveyed into the substrate processing equipment that has the wafer stage to which the above 31254 foreign matters were adhered, the wafer could be conveyed without trouble. Then, the new 8-inch silicon wafers to which the 10 foreign matters having the size of more than 0.2 μm were conveyed while directing the mirror surface downward and then the foreign matters having the size of more than 0.2 μm were counted by the laser foreign-matter measuring device. This operation was repeated five times, and the results are shown in Table 3.

EXAMPLE 8

The cleaning sheet B was prepared in the same way as Example 7 except that the ultraviolet curing adhesive solution B, that was obtained by mixing uniformly the multifunctional urethane acrylate (product name UV1700B manufactured by The Nippon Synthetic Chemical Industry, Co., Ltd.) 100 parts and the polyisocyanate compound (product name Colonate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 3 parts, and the benzyldimethylketal (product name Illugacure 651 manufactured by Chiba-Speciality Chemicals Co., Ltd.) 10 parts as the photopolymerization initiator into the acrylic polymer (weight-average molecular weight 2800000) 100 parts obtained from the monomer mixed solution consisting of the acrylic acid-2-ethyl hexyl 75 parts, the methyl acrylate 20 parts, and the acrylic acid 5 parts, as the ultraviolet curing adhesive. When the modulus of elasticity in tension of this ultraviolet curing adhesive B was measured, 0.01 N/mm2 was obtained before the curing, while 1440 N/mm2 was obtained after the ultraviolet rays having the central wavelength 365 nm were irradiated up to the integrated quantity of light 1000 mJ/cm2.

When 25 sheets of wafers with sheets were fabricated by the direct cutting system using this cleaning sheet B like Example 7, the cutting scobs were not generated at all in cutting the sheet. Then, the conveying cleaning wafer B with the cleaning function was fabricated by irradiating the ultraviolet rays having the central wavelength 365 nm to five sheets of these wafers up to the integrated quantity of light 1000 mJ/cm2.

Then, when the releasing film on the cleaning layer side of the resultant conveying cleaning wafer A was peeled off and then the wafer was conveyed into the substrate processing equipment that has the wafer stage to which the above 29954 foreign matters are adhered, the wafer could be conveyed without trouble. Then, the new 8-inch silicon wafers to which the 10 foreign matters having the size of more than 0.2 μm were conveyed while directing the mirror surface downward and then the foreign matters having the size of more than 0.2 μm were counted by the laser foreign-matter measuring device. This operation was repeated five times, and the results are shown in Table 3.

Comparative Example 7

When the wafers with sheets were fabricated by the direct cutting system similarly except that the cleaning sheet C was fabricated by irradiating the ultraviolet rays having the central wavelength 365 nm up to the integrated quantity of light 1000 mJ/cm2 before the wafer was pasted onto the cleaning sheet A in Example 7, a large amount of cutting scobs were generated from the cleaning layer in cutting the sheet. Thus, a number of cutting scobs were stuck onto the edges of the wafers with the sheet, the back surface of the wafer, and the tape pasting device. Accordingly, the fabrication of the wafer C with the sheet was interrupted.

Comparative Example 8

The cleaning sheet D was fabricated in the same way as Example 7 except that the pressure-sensitive adhesive solution A shown in Example 8 was employed as the adhesive for the cleaning layer. In this case, the modulus of elasticity in tension of the cleaning layer was 0.1 N/mm2.

When the wafers with sheets were fabricated by the direct cutting system in the same way as Example 7 from the cleaning sheet D, no cutting scob was generated in cutting the sheet and thus 25-sheets of wafers could be fabricated. When these conveying cleaning wafers D were conveyed into the substrate processing equipment that has the wafer stage to which the 27986 foreign matters were adhered, the first wafer wais stuck to the wafer stage and thus could not be conveyed.

Industrial Applicability

As described above, according to the cleaning sheet of the present invention, the substrate can be conveyed in the substrate processing equipment without fail and also the foreign matters adhered onto the equipment can be simply reduced.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form can be changed in the details of construction and in the combination and arrangement of parts without departing from the spirit and the scope of the invention as hereinafter claimed.

CLAIMS

1. A cleaning sheet comprising a cleaning layer having a surface resistivity more than 1×1013 Ω/□.

2. A cleaning sheet set forth in claim 1, further comprising a base material for supporting said cleaning layer.

3. A cleaning sheet set forth in claim 1, further comprising: a base material having one surface on which said cleaning layer is provide; and an adhesive layer being on an other surface of said base material.

4. A cleaning sheet according to claim 1, wherein a relative dielectric constant of the cleaning layer is larger than 2.0.

5. A cleaning sheet according to claim 1, wherein a surface free energy of the cleaning layer is not less than 30 mJ/m2.

6. A cleaning sheet according to claim 5, wherein a contact angle with respect to water of the cleaning layer is not more than 90 degrees.

7. A cleaning sheet according to claim 1, wherein a surface potential of the cleaning layer exceeds 10 kV.

8. A cleaning sheer according to claim 7, wherein the cleaning layer is formed as an electret by a thermal electret method.

9. A cleaning sheet according to claim 1, wherein the cleaning layer does not substantially have a tackiness.

10. A cleaning sheet according to claim 1, wherein a modulus of elasticity in tension according to test method JIS K7127 of the cleaning layer is 1 to 3000 N/mm2.

11. A cleaning sheet according to claim 1, wherein the cleaning layer is formed of an adhesive layer that is cured by an active energy.

12. A conveying member with a cleaning function in which the cleaning sheet set forth in claim 3 is provided to a conveying member via an adhesive layer.

13. A substrate processing equipment cleaning method of conveying the cleaning sheet set forth in claim 1 or the conveying member set forth in claim 12 into a substrate processing equipment.

14. A cleaning member which is a cleaning member for a conduction testing equipment and in which the cleaning sheet set forth in claim 1 for removing foreign matters adhered onto a contacted surface of the equipment, with which a contact pin cleaner comes into contact, is provided to one surface of a member for removing foreign matters adhered to a conduction testing contact pin of the equipment.

15. A cleaning member which is a cleaning member for a conduction testing equipment and in which a contact pin cleaner for removing foreign matters adhered onto a conduction testing contact pin of the equipment is provided to one surface of a conveying member, and the cleaning sheet set forth in claim 1 for removing the foreign matters adhered to a contacted surface of the equipment, with which the contact pin cleaner comes into contact, is provided to an other surface of the conveying member.

16. A cleaning member according to any one of claims 14 and 15, wherein, in the cleaning sheet, an adhesive layer is provided onto one surface of a base material and a cleaning layer for removing the foreign matters adhered to the contacted surface of the equipment, with which the contact pin cleaner comes into contact, is provided onto an other surface of the base material.

17. A cleaning sheet according to claim 1, wherein a coefficient of friction of the cleaning layer is not less than 1.0.

18. A cleaning sheet according to claim 1, wherein the adhesive layer is a curing adhesive that contains a pressure-sensitive adhesive polymer, a polymerized unsaturated compound that has one upsaturated double bond or more in a molecule, and a polymerization initiator.

19. A conduction tester cleaning method of conveying the cleaning member set forth in any one of claims 14 and 15 into a conduction tester.

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